Broadcasting signal transmission and reception method and device

ABSTRACT

The present invention relates to a device and method for transmitting and receiving a broadcasting signal including a subtitle service. An embodiment of the present invention provides a broadcasting signal transmission method comprising the steps of: generating a broadcasting signal including video data and subtitle data; and transmitting the generated broadcasting signal. According to an embodiment of the present invention, a transmission stream providing a digital broadcasting subtitle service using XML subtitles can be transmitted.

TECHNICAL FIELD

The present invention relates to a device and a method for transmittingand receiving broadcast signals.

BACKGROUND ART

With the development of digital technology and communication technology,a demand for and propagation of audio/video based multimedia content arerapidly increasing in various areas such as Internet and personal mediaas well as broadcast and movies. Furthermore, a consumer demand forimmersive media which provide sense of reality through broadcast andmovies is increasing. In addition, as home TV screens become large withthe development of display technology, demand for realistic content withmore than high definition (HD) is increasing. Realistic broadcastingsuch as UHDTV (Ultra High Definition TV) along with 3DTV attractsattention as a future broadcast service. Particularly, a discussionabout UHD broadcast services is increasingly conducted.

DISCLOSURE Technical Problem

An object of the present invention is to improve transmission efficiencyin a method and a device for transmitting a broadcast signal.

Another object of the present invention is to provide a transmissiondevice and method for transmitting metadata for dynamically providingbrightness representation and color representation of content.

Technical Solution

A method of transmitting a broadcast signal according to an embodimentof the present invention includes: generating video data; generating abroadcast signal including the generated video data and video qualityenhancement metadata; and transmitting the generated broadcast signal.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the video quality enhancementmetadata may include high dynamic range (HDR) information or wide colorgamut (WCG) information.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the HDR information or the WCGinformation may be applied to all or some sections of the video data.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the HDR information or the WCGinformation may be applied to the some sections of the video data inunits of scene or frame.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the video quality enhancementmetadata may further include synchronization information indicating atime at which the HDR or the WCG information is applied to the videodata.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the video quality enhancementmetadata may further include type information indicating an applicationrange of the HDR or WCG information.

A method of receiving a broadcast signal according to an embodiment ofthe present invention includes: receiving a broadcast signal includingvideo data and video quality enhancement metadata; demultiplexing thebroadcast signal into the video data and the video quality enhancementmetadata; decoding the video data and the video quality enhancementmetadata; and applying the video quality enhancement metadata to thevideo data.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the video quality enhancement metadata mayinclude high dynamic range (HDR) information or wide color gamut (WCG)information.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the HDR information or the WCG information maybe applied to all or some sections of the video data.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the HDR information or the WCG information maybe applied to the some sections of the video data in units of scene orframe.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the video quality enhancement metadata mayfurther include synchronization information indicating a time at whichthe HDR or the WCG information is applied to the video data.

In the method of receiving a broadcast signal according to an embodimentof the present invention, the video quality enhancement metadata mayfurther include type information indicating an application range of theHDR or WCG information.

A broadcast signal transmission device according to an embodiment of thepresent invention includes: an encoder for generating video data; amultiplexer for generating a broadcast signal including the generatedvideo data and video quality enhancement metadata; and a transmitter fortransmitting the generated broadcast signal.

A broadcast signal reception device according to an embodiment of thepresent invention includes: a receiver for receiving a broadcast signalincluding video data and video quality enhancement metadata; ademultiplexer for demultiplexing the broadcast signal into the videodata and the video quality enhancement metadata; a decoder for decodingthe video data and the video quality enhancement metadata; and a postprocessor for applying the video quality enhancement metadata to thevideo data.

Advantageous Effects

According to embodiments of the present invention, it is possible toimprove transmission efficiency of a broadcast system.

According to the embodiment of the present invention, a broadcastnetwork can provide dynamic luminance representation and colorrepresentation for each piece of content.

According to the embodiment of the present invention, a broadcastnetwork can provide dynamic luminance representation and colorrepresentation per scene in content.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a reception device that receives a metadata based HDRbroadcast service according to an embodiment of the present invention.

FIG. 2 illustrates an operation method of a receiver for HDR videoaccording to an embodiment of the present invention.

FIG. 3 illustrates a post processor according to an embodiment of thepresent invention.

FIGS. 4 to 7 illustrate syntaxes of an SEI message and an HDR videoinformation descriptor according to an embodiment of the presentinvention.

FIG. 8 illustrates an embodiment of signaling metadata informationaccording to RAP.

FIG. 9 illustrates dynamic_range_mapping_info according to an embodimentof the present invention.

FIG. 10 illustrates a case in which an SEI message defined in HEVC isreferred to according to an embodiment of the present invention.

FIGS. 11 and 12 illustrate an embodiment of signaling an HDR_video_infodescriptor according to an embodiment of the present invention through aPMT.

FIGS. 13 and 14 illustrate an embodiment of signaling the HDR_video_infodescriptor according to the embodiment of the present invention throughan EIT.

FIG. 15 illustrates HDR_video_info_descriptor( ) according to anotherembodiment of the present invention.

FIG. 16 is a block diagram of a receiver and illustrates operation ofthe receiver according to an embodiment of the present invention.

FIG. 17 is a block diagram of a broadcast transmitter according to anembodiment of the present invention.

FIG. 18 is a block diagram of a broadcast receiver according to anembodiment of the present invention.

FIG. 19 illustrates a method of transmitting a broadcast signalincluding video quality enhancement metadata according to an embodimentof the present invention.

FIG. 20 illustrates a method of receiving a broadcast signal includingvideo quality enhancement metadata according to an embodiment of thepresent invention.

BEST MODE

The present invention can provide a method for converting and presentingcontent as images with enhanced video quality by transmitting, to areceiver, a factor which can adaptively adjust the content forcharacteristics of various scenes included in the content when highdynamic range (HDR) content which can be represented in a wide range ofluminance is provided. UHD broadcast can be discriminated from previousbroadcast and can provide high level of presence by representingluminance which cannot be expressed in previous content. As a dynamicrange of images increases according to introduction of HDR (high dynamicrange), a characteristic difference between scenes included in contentmay increase. Accordingly, a broadcast transmission device canadditionally provide information for effectively displayingcharacteristics of each scene on a display and a reception device canpresent images through a method suitable for a producer's intention byproviding video effects on the basis of the transmitted information.

UHD broadcast can provide enhanced video quality and immersiveness toviewers through various methods compared to HD broadcast. As one of themethods, UHD broadcast can provide a method of extending ranges ofrepresentation of luminance and color expressed in content to luminanceand color recognition ranges which can be recognized by the human visualsystem. That is, HDR (high dynamic range) and WCG (wide color gamut) canbe applied to UHD content. That is, content with enhanced high contrastand colors is provided such that a UHD content user can experienceimproved immersiveness and presence. The present invention provides amethod for effectively presenting luminance and color of images ofcontent depending on intention of a producer when the content ispresented through a display such that a user can view images withenhanced video quality.

FIG. 1 illustrates a reception device for receiving a metadata based HDRbroadcast service according to an embodiment of the present invention.The reception device may include at least one of a demultiplexer 101, adecoder 102, a metadata processor 103, a post processor 104, asynchronizer 105 and a display 106. While metadata included in a videostream and received is illustrated in the figure, metadata according tothe present invention may be transmitted and received through otherpaths (e.g., IP based broadcast/communication, wired/wirelesscommunication, wired/wireless interfaces, short-range wirelesscommunication, etc.) as well as broadcast signals. The demultiplexer 101may receive and demultiplex an HDR stream. A single HDR stream mayinclude multiple pieces of content, and the demultiplexer may output anHDR stream which is a decoding target to the decoder.

The decoder 102 may receive and decode the HDR stream. In this process,the decoder may output decoded HDR video and HDR metadata. The decodedHDR video may be output to the post processor and the HDR metadata maybe output to the metadata processor.

The metadata processor 103 may receive and store the HDR metadata. Themetadata processor may check whether the stored HDR metadata has beenchanged by checking a set number or a version number included in the HDRmetadata and update existing HDR metadata when the stored HDR metadatahas been changed. The metadata processor may output the HDR metadata tothe post processor according to timing information received from thesynchronizer.

The post processor 104 may perform post-processing on the HDR videoreceived from the decoder using the HDR metadata received from themetadata processor. Through this process, the HDR video can be convertedto enhanced HDR video in which the HDR metadata has been reflected.

The synchronizer 105 may provide timing information to the metadataprocessor and the post processor such that metadata is applied to theHDR video, each scene thereof or each frame thereof at correct timing.

The HDR display 106 may display and provide the enhanced HDR video to auser.

FIG. 2 illustrates an operation method of a receiver for HDR videoaccording to an embodiment of the present invention.

When a video stream is received, the receiver may separate HDR metadatafrom an HDR video signal using a video decoder 201 and store theseparated HDR metadata in a separate metadata parser 202. The metadataprocessor may include a metadata parser, a metadata buffer and ametadata update unit. The HDR metadata may include common HDR metadataand scene/frame HDR metadata. The common HDR metadata is applicable toentire content and the scene/frame HDR metadata is limitedly applicableto part of content. Here, part of content can be defined as a scene, aframe or a time period. The receiver may determine the type of contentwhich can be presentable and then process the content by applying thecommon HDR metadata or the scene/frame HDR metadata thereto. Thereceiver which can present HDR video may convert the content usingreceived metadata. The receiver may display the converted content afterprocessing as a final image. A detailed operation method of the receiverwill be described below.

In the first step, the receiver may decode the video stream to acquirethe HDR metadata. The HDR metadata may refer to HDR video information(referred to as HDR_video_infor( ) hereinafter). The receiver maydeliver the metadata acquired from the video stream to the metadataparser 202, analyze the metadata and store the metadata in a memory. Themetadata may be divided into common HDR metadata and scene/frame HDRmetadata. The present invention can indicate application of the commonHDR metadata or the scene/frame HDR metadata to a unit such as content,mastering display, a scene section or a single frame by delivering arange of application of the metadata using type informationHDR_video_info_type which will be described below. The metadata mayfurther include a section to which the metadata is applied, for example,information for matching the metadata with a video frame to which themetadata is applied, in the form of synchronization start informationsync_start and synchronization duration information sync_duration.

According to an embodiment, the common HDR metadata may include at leastone of a value indicating the dynamic range of content/masteringdisplay/frame, such as maximum/minimum luminance or high contrast, atransfer function such as EOTF, the color gamut of the content ormastering display, the color temperature of the content or masteringdisplay, a dynamic range transfer function, a color gamut transferfunction and viewing condition information.

In the specification, the value indicating the dynamic range of thecontent/mastering display/frame may be transmitted usingdynamic_range_info_type and dynamic_range_Info_value[i]. The transferfunction such as EOTF may be transmitted using transfer_function_type.The color gamut of the content or mastering display may be transmittedusing color_gamut_type. The color temperature of the content ormastering display may be transmitted using color_temperature_type. Thedynamic range transfer function may be transmitted usingdynamic_range_mapping_info_type. The color gamut transfer function maybe transmitting using color_gamut_mapping_info_type. The viewingcondition information may be transmitted usingviewing_condition_info_type. The syntax of information and fieldsincluded therein will be described below.

The scene/frame HDR metadata may include information identical orsimilar to the common HDR metadata and may also include informationabout a range to which the scene/frame HDR metadata is applied. Thescene/frame HDR metadata can deliver more specific information becausethe range to which the scene/frame HDR metadata is applied is limited tosome parts of content. For example, the common HDR metadata can delivera dynamic range applied to entire content as a value such as f-stop orhigh contrast, whereas the scene/frame HDR metadata can deliver maximumand minimum values for a frame unit to achieve delivery of more specificinformation. Accordingly, different information delivery ranges can beapplied to steps according to types of delivered metadata. Similarly, inthe case of dynamic range mapping, information regarding transformationof overall content may be delivered as the common HDR metadata and thena complicated transfer function capable of representing characteristicsof each scene may be delivered through the scene/frame HDR metadata.

In the second step, the receiver may determine whether the displayincluded therein is an HDR display. The receiver may determine whether apresentation condition of the receiver is suitable on the basis ofinformation about the acquired content (or information about masteringdisplay) using common information. For example, the receiver may use theaforementioned common HDR metadata and may consider an SDR display or adisplay having performance between SDR and HDR if the contentpresentation condition is not suitable.

A case in which the display included in the receiver is an SDR displayor a display having performance equivalent thereto will be describedfirst. Upon determining that the receiver display cannot completelypresent decoded HDR content, the receiver may not present the HDRcontent or may perform conversion for content presentation. A receiverthat can convert HDR video into SDR video can convert received HDR videointo SDR video and present the SDR video. To this end, HDR metadata mayinclude information about a transfer function for converting HDR videointo SDR video. For example, dynamic_range_mapping_info_type orcolor_gamut_mapping_info_type may be used as the information about thetransfer function, and the HDR metadata may additionally signal use ofthe information to convert HDR video into SDR video as necessary.

Next, a case in which the display included in the receiver is an HDRdisplay will be described. This corresponds to a case in which thedisplay of the receiver is determined to be able to completely presentdecoded content. In this case, video quality can be enhanced using thecommon HDR metadata included in the HDR metadata, and video qualityenhancement can be achieved using dynamic range mapping, color gamutmapping and viewing condition mapping. According to an embodiment, videoquality enhancement for content using the common HDR metadata may beomitted when the scene/frame HDR metadata can be applied in the thirdstep which will be described below. Further, video quality enhancementusing the common HDR metadata may be realized using an additional moduleor applied in association with a post processing module which will bedescribed with reference to FIG. 3.

In the third step, the receiver may perform video quality enhancementper scene of HDR video. When it is determined that the receiver canpresent HDR content on the basis of metadata information, the receivermay determine whether the receiver can process additional HDR metadata.

FIG. 2 shows a case in which scene-by-scene (or frame-by-frame)processing is additionally performed. In this case, it is possible todisplay HDR video with enhanced quality through detailed dynamicconversion per scene or frame of content using metadata provided on ascene-by-scene or frame-by-frame basis. Here, a broadcast transmissiondevice can cause the receiver to identify transmission of information inunits of scene or frame through a supplemental enhancement information(SEI) message using HDR_video_info_type according to an embodiment ofthe present invention. Furthermore, the broadcast transmission devicecan provide, to the receiver, information about a time at which theinformation in units of scene or frame needs to be applied usingsync_info_type, sync_start and sync_duration. The receiver can identifytransmission of the information in units of scene or frame throughHDR_video_info_type and acquire timing information about the time atwhich the information in units of scene or frame is applied throughsync_info_type, sync_start and sync_duration. In addition, the receivermay convert the timing information provided through metadata intoinformation for synchronization with images as necessary.

In addition, the broadcast transmission device may inform the receiverof the type of metadata in units of scene or frame which will beprovided when providing the common HDR metadata. The broadcasttransmission device may previously inform the receiver of theaforementioned information throughHDR_video_enhancement_info_present_type. That is, the receiver canacquire information about whether the scene/frame HDR metadata isreceived and the type thereof from the common HDR metadata and prepareto operate a related module. According to an embodiment, the broadcasttransmission device may indicate the fact that the metadata in units offrame or scene is provided or indicate presence of information in unitsof frame or scene using the common HDR metadata. For example, thebroadcast transmission device can indicate provision of dynamic rangemapping and/or color gamut mapping information in units of frame orscene using the common HDR metadata.

According to an embodiment, the receiver may apply the common HDRmetadata and scene HDR metadata to HDR video in stages or apply the samethrough one operation. Further, the receiver may apply the common HDRmetadata and scene HDR metadata to the HDR video per dynamic rangemapping and color gamut mapping or apply the same through one transferformula.

FIG. 3 illustrates a post processor according to an embodiment of thepresent invention. In the present invention, the post processor mayinclude a dynamic range (DR) mapping block 301, a color gamut (CG)mapping block 302 and a viewing condition adjustment block 303. The postprocessor may receive HDR video data and perform video qualityenhancement using dynamic range mapping, color gamut mapping and viewingcondition mapping. The DR mapping block 301 may perform video qualityenhancement by applying dynamic range information, transfer functioninformation and DR mapping information to the input HDR video data. TheCG mapping block 302 may perform video quality enhancement by applyingcolor gamut information, color temperature information and CG mappinginformation to the input HDR video data. The viewing conditionadjustment block 303 may perform video quality enhancement by applyingviewing condition information to the HDR video data. Details of theinformation will be described below with reference to FIGS. 4 to 15.

FIGS. 4 to 7 illustrate syntaxes of an SEI message and HDR videoinformation descriptors according to an embodiment of the presentinvention.

An SEI message may include an HDR video information descriptor, and theHDR video information descriptor may include at least one of thefollowing fields.

HDR_video_info_type can indicate a unit of application of information inthe HDR video information descriptor. That is, HDR_video_info_type canspecify an application unit such as common application to a video clip(common type), application within consecutive scenes (scene type) andapplication to each frame (frame type). The aforementioned common HDRmetadata may be represented as the common type and the scene/frame HDRmetadata may be represented as the scene type or frame type. The upperpart of FIG. 5 shows an embodiment of HDR_video_info_type. The broadcasttransmission device may set HDR_video_info_type to the common type andtransmit information about content in order to deliver common typeinformation. In addition, the broadcast transmission device may transmitinformation that refers to an SEI message in order to deliver the commontype information. In this case, the receiver may use a predetermined SEImessage as the common type information. For example, the broadcasttransmission device may designate an SEI message included in HEVC or amastering display color volume SEI message as an SEI message which is areference target. Further, the broadcast transmission device maytransmit information about mastering display in order to deliver thecommon type information. In this case, the receiver may receiveinformation about mastering display and use the information as thecommon type information. In addition, the receiver may deliver a kneefunction information SEI message or a color remapping information SEImessage among HEVC SEI messages to apply the same to entire content. Ifsuch information varies with time like a scene or a frame, it ispossible to indicate that the information is applied only to a scene ora frame which is part of the content by setting HDR_video_info_type tothe scene type or frame type in the corresponding time unit anddelivering the corresponding SEI message or detailed information

Set_number can indicate an identification number unique to an HDR videoinformation descriptor. That is, when a plurality of HDR videoinformation descriptors is delivered in units of time or frame from thebroadcast transmission device to the receiver, set_number candiscriminate the HDR video information descriptors. Set_number maydiscriminate a plurality of descriptors for types such as the commontype, frame type and scene type in association with the aforementionedHDR_video_info_type as necessary.

Version_number can indicate the version of the HDR video informationdescriptor. Version_number can indicate an information change in thecurrent descriptor in association with at least one ofHDR_video_info_type and set_number. For example, when a descriptorhaving the same HDR_video_info_type and/or the same set_number has thesame version number as the previous version number, information in ametadata processor can be applied to images intact. However, if thedescriptor has a different version number, it is possible to determinethat information has been updated, apply new metadata information toimages and replace information in the metadata processor with updatedinformation.

Dynamic_range_mapping_info_present_flag can indicate that dynamic rangemapping related information is included in the descriptor.

Color_gamut_mapping_info_present_flag can indicate that gamut mappingrelated information is included in the descriptor.

Viewing_condition_info_present_flag can indicate that viewing conditionrelated information is included in the descriptor.

HDR_video_enhancement_info_present_type can indicate whether informationregarding each scene or frame is additionally delivered. For example,when HDR_video_info_type indicates the common type,HDR_video_enhancement_info_present_type can indicate whether dynamicrange mapping or gamut mapping related information is additionallydelivered. Here, the role of additional information may be defined perframe or scene as shown in the lower part of FIG. 5. The role ofadditional information may be dynamic range mapping or gamut mapping.Accordingly, the receiver can prepare processing operation foradditional information.

Sync_info_type can indicate a method of representing information forsynchronization with video, a scene or a frame to which information inthe HDR video information descriptor needs to be applied. For example,sync_info_type can deliver a picture order count (POC) value used in adecoder or directly deliver a pic_order_count_lsb value. In the case ofstorage media, media time information can be used, and the number ofaccumulated frames on the basis of a reference time for video start maybe decided as sync_info_type.

Sync_start is information related to synchronization start time. Wheninformation is delivered in a specific period such as an RAP instead ofbeing delivered per frame, it is necessary to connect the start and endof a period in which the information is used to video frames. Thepresent invention may apply an embodiment of representing startinformation of the period or a frame to which the correspondinginformation is applied as information such as a time, a POC, the numberof frames or PTS in association with sync_info_type using sync_start.Sync_info_type can define a synchronization information type as a time,a time difference, start order, a POC (picture order count), PTS or thenumber of aggregated frames.

For example, it is possible to consider a case in which three pieces ofmetadata are applied to 2 seconds (start time), 2.5 seconds and 3.5seconds within an RAP of 2 to 4 seconds for a 50 fps video stream havingan RAP interval of 2 seconds.

When sync_info_type=0x00, the synchronization information type can beset to time and sync_start information of the metadata can be deliveredas 2000, 2500 and 3500. Additionally, sync_duration can be signaled as500, 1000 and 1000. Here, a reference time may be needed fordetermination of time. In this case, the reference time may beadditionally signaled in such a manner that a time is defined in anadaptation field of a TS header.

When sync_info_type=0x01, the synchronization information type can beset to a time difference. The broadcast transmission device can informthe receiver of immediate application of metadata, application of themetadata after 0.5 seconds from RAP and application of metadata after1.5 seconds from RAP by signaling sync_start=0, 500 and 1000.

When sync_info_type=0x02, the synchronization information type can beset to a start order and the order can be signaled like sync_start=0, 1,2. When the start order is signaled, the receiver can applysynchronization information in the order at a specific interval. Thespecific interval may be a fixed value or may be a value determined inthe order. For example, 0 can indicate immediate application, 1 canindicate application after 0.5 seconds from RAP, and 2 can indicateapplication after 1.5 seconds after RAP.

When sync_info_type=0x03, the synchronization information type can beset to a POC. In this case, 100, 125 and 175 may be delivered as POCvalues of video at metadata application timing, and 25, 50 and 50 may bedelivered as duration values which will be described below depending onthe unit of the POC. Further, values related to a POC in a video codecsyntax may be directly delivered.

When a PTS (presentation time stamp) and the number of frames aresignaled, a metadata application timing can be indicated through the PTSand the number of frames similarly to the aforementioned example of thePOC.

Sync_duration is information about a duration starting from sync_start.A synchronization expiration timing can be calculated assync_start+sync_duration as in the aforementioned example, andsynchronization expiration timing information may be directly deliveredalong with or instead of sync_duration as necessary. In the case of livebroadcast, an expiration time cannot be determined in advance and thusmay be set to a predetermined value such as FFFF. If the metadataapplication timing can be determined only with the sync_startinformation, sync_duration may not be used. In this case, sync_durationmay be used as a flag that provides additional information such asinformation indicating whether other metadata is transmitted followingthe corresponding metadata.

Number_of_dynamic_range_info can indicate the number of methods ofrepresenting dynamic range information corresponding to masteringdisplay, video, a scene or a frame.

Dynamic_range_info_type indicates a method of representing dynamic rangeinformation corresponding to mastering display, video, a scene or aframe. Methods for representing a dynamic range may be as shown in thelower part of FIG. 6. A dynamic range can be represented using at leastone of maximum luminance, minimum luminance, average luminance, and anaverage or median value composed of a specific component. Further, whitemay be subdivided into normal white, diffuse white and specular whiteaccording to characteristics and black may be classified into normalblack, deep black and pitch dark according to characteristics andpresented.

As described in the example below, the broadcast transmission device cansubdivide and represent luminance of a bright part and a dark part ofcontent by providing information such as specular white and pitch darkthrough HDR video info, and such information can be used as a criterionfor determination of receiver display conditions or as information formapping according to display conditions.

Ex) video DR: peak luminance=4000 nit, minimum_luminance_level=0.01 nit

A scene DR discriminated from a video DR may be represented in detailsuch as scene DR: white_level_A=1000 nit, white_level_B=2000 nit,black_level_A=0.1 nit, black_level_B=0.01 nit, anddynamic_range_info_type may be used to represent a container DR and ascene DR in a discriminative manner.

Transfer_function_type can indicate the type of a transfer function usedfor mastering display, video, a scene or a frame of HDR video. Forexample, predetermined EOTF such as SMPTE ST 2084, ITU BT.1886 andBT.2020 can be signaled. Luminance representation methods may be dividedinto an absolute luminance representation method and a relativeluminance representation method depending on the type of a transferfunction and a specific method may be signaled. A coefficient of anarbitrary transfer function may be delivered as necessary.

Color_gamut_type can indicate a color gamut type corresponding tomastering display, video, a scene or a frame of HDR video. For example,color_gamut_type can indicate a standard color gamut such as BT.709,BT.2020 and DCI-P3 or indicate an arbitrary color gamut through RGBcolor primary (XYZ, RGBW and the like may be used) as necessary.

Color_temperature_type can indicate information about standard whitecorresponding to mastering display, video, a scene or a frame of a colorgamut. For example, color_temperature_type may be a standard lightsource color temperature such as D65 and D50 and may indicate anarbitrary value representative of a color temperature such as RGB colorprimary (XYZ, RGBW and the like are possible) with respect to white asnecessary.

Dynamic_range_mapping_info_type indicates the type of dynamic rangemapping information corresponding to mastering display, video, a sceneor a frame. For example, dynamic_range_mapping_info_type can refer to aknee function information SEI message or a tone mapping information SEImessage included in HEVC, as shown in the upper part of FIG. 7.Furthermore, dynamic_range_mapping_info_type may be directly describedin a predetermined HDR video information descriptor.

Color_gamut_mapping_info_type indicates the type of color gamut mappinginformation corresponding to mastering display, video, a scene or aframe. For example, color_gamut_mapping_info_type can refer toinformation defined in a color remapping information SEI messageincluded in HEVC, as shown in the low part of FIG. 7. Further,color_gamut_mapping_info_type may be directly described in apredetermined HDR video information descriptor.

Viewing_condition_info_type indicates the type of viewing conditioninformation corresponding to video, a scene or a frame. For example,viewing_condition_info_type may refer to information defined inviewing_condition defined as a separate SEI message and may be directlydescribed in a predetermined HDR video information descriptor.

When an external SEI message is referred to for the aforementioneddynamic_range_mapping_info_type, color_gamut_mapping_info_type andviewing_condition_info_type, a method of directly signaling payloadTypeof the SEI message may be used, distinguished from the aforementionedmethod. For example, when a knee function information SEI message isreferred to, a signaling method using dynamic_range_mapping_info_type=0and payloadType=141 may be used.

FIG. 8 illustrates a method of signaling metadata information with timeaccording to an embodiment of the present invention.

For metadata transmission with time, various methods such as 1) a methodof transmitting all of corresponding information for each frame, 2) amethod of transmitting metadata in frames corresponding to a period inwhich the metadata is changed and applied within an RAP, 3) a method ofsimultaneously transmitting metadata applied within a period such as anRAP in the period, and 4) a method of transmitting metadata prior to anRAP related to an application timing can be conceived. Further, acombination of methods 1) to 4) may be used.

FIG. 8 illustrates an embodiment of signaling metadata informationaccording to RAP. The common type applied to entire video can betransmitted in each RAP. This corresponds to a case in whichHDR_video_info_type is set to 0000 in FIG. 8. Although the common typeis repetitive information, the broadcast transmission device cancompensate for information loss due to transmission error bytransmitting the common type per RAP.

When information applied differently for each scene needs to beprovided, the information may be transmitted using scene metadata. Thiscorresponds to a case in which HDR_video_info_type is set to 0100 inFIG. 8. In this case, information corresponding to an RAP andinformation applied after scene change in the RAP can be transmittedtogether. Information corresponding to an RAP and information appliedafter scene change in the RAP may be defined as sets having differentroles and may be discriminated from each other by being assigneddifferent set numbers. According to an embodiment, when pieces ofinformation having different roles are separately delivered even thoughthe information is applied to the same scene, different set numbers canbe used to discriminate the information. When information is appliedover two or more RAPs, the information has the same set_number and, whendetailed information is not updated, the same version_number is set forthe information. When detailed information is changed, the informationmay have a different version_number such that the metadata processor canidentify a set having information update and determine whether toperform update. When the next RAP arrives, a scene start time changes tothe new RAP and thus sync_start can change to the new RAP and can beapplied. In this case, when a sync duration end point(sync_start+sync_duration) is not changed, the same version_number canbe applied upon determining that there is no information change.

When application information is previously transmitted before arrival ofan RAP related to a metadata application timing used in a program,application timing can be signaled through a relative concept such as atime difference, order and the number of frames. In this case, it may bepossible to signal that the corresponding metadata is not applied in thecorresponding RAP but will be applied later using predeterminedsignaling such as sync_start=FFFF or a method of signaling with a longerduration than an RAP.

In FIG. 8, sync_start=0 and sync_duration=180 can be set for the secondHDR_video_info_type=0100 in a period of 00:00:00:00 to 00:00:02:00, andsync_start=0 and sync_duration=60 can be set for the secondHDR_video_info_type=0100 in a period of 0:00:02:00 to 00:00:04:00. Asstart time changes from 00:00:00:00 to 00:00:02:00, duration can bechanged and signaled for the same information (set 1, ver 0). Thereceiver does not perform metadata update when it is confirmed that themetadata has not been changed.

When details of information that plays the same role as previousinformation have been changed, the broadcast transmission device canincrease version_number of common HDR metadata while maintainingset_number thereof. The metadata processor of the receiver can recognizeinformation change on the basis of changed version_number and updateprevious information to new information.

When information has been changed in the metadata in a period of00:00:04:00 to 00:00:06:00 as shown in FIG. 8, information such as starttime may be additionally delivered. When information has been changed inthe metadata, for example, when information B has been changed toinformation B′, a new version number can be assigned. It can beconfirmed from the figure that the version number for set_number=2 is 0in the period of 00:00:02:00 to 00:00:04:00 but the version number hasincreased to 1 in the period of 00:00:04:00 to 00:00:06:00. It is alsopossible to signal that update needs to be performed when expirationtime is changed.

FIG. 9 illustrates dynamic_range_mapping_info according to an embodimentof the present invention. When dynamic_range_mapping_info_type describedabove with reference to the upper part of FIG. 7 is set to 0x03,dynamic_range_mapping_info( ) can be directly defined in theHDR_video_info descriptor. When HDR_video_info_type is common type ascommon HDR metadata related to mastering display or video, informationdescribed with reference to FIG. 9 can be used for the entire video.When HDR_video_info_type is scene type or frame type as scene/frame HDRmetadata, the information described with reference to FIG. 9 can be usedfor a corresponding section. Fields included indynamic_range_mapping_info( ) will be described below.

Dynamic_range_mapping_info( ) according to an embodiment of the presentinvention may include luminance_max, luminance_min, private_EOTF,number_of_coeff, transfer_curve_coeff[i], clipping_flag,linear_mapping_flag, luma_clipping_upper_bound,luma_clipping_lower_bound, luminance_upper_bound, luminance_lower_bound,luma_upper_value, luma_lower_value, mid_DR_transformation_curve_type,mid_DR_transformation_curve( ), mid_DR_percentage,upper_DR_transformation_curve_type, upper_DR_transformation_curve( ),upper_DR_percentage, lower_DR_transformation_curve_type,lower_DR_transformation_curve( ), number_luminance_upper_bound_diff,luminance_upper_bound_diff[i], luma_upper_value_diff[i],upper_DR_transformation_curve_type[i], upper_DR_transformation_curve( ),upper_DR_percentage[i] and/or mid_DR_percentage[i].

Luminance_max indicates maximum reference luminance represented in UHDbroadcast content. That is, this indicates a maximum value of a dynamicrange (DR). For example, in the case of a reference monitor, 100 cd/m̂2is decided as maximum reference luminance. In this case, 1, which is thequotient of a value obtained by dividing the above value by 100 (decimalnumber) in consideration of a general range, can be transmitted.

Luminance_min indicates minimum reference luminance represented in UHDbroadcast content. That is, this indicates a minimum value of thedynamic range. For example, in the case of a reference monitor, 0.05cd/m̂2 is decided as minimum reference luminance. In this case, 5obtained by multiplying the above value by 100 (decimal number) inconsideration of a general range can be transmitted.

Private_EOTF indicates whether any EOTF function is used. This can bedelivered through VUI information when a widely-used EOTF such as ITU-RBT.1886, REC.709 and BT.2020 is used. However, when an EOTF which hasnot been decided as standard is used, the corresponding field value canbe set to 1. For example, perceptual quantization can be used as an EOTFwhich has not been decided as standard, that is, arbitrary EOTF.

number_of_coeff indicates the number of coefficients used for anarbitrary EOTF.

transfer_curve_coeff[i] indicates a coefficient used for an arbitraryEOTF.

clipping_flag indicates whether a clipping option is used and can have avalue of 1 when use of the clipping option is permitted.

linear_mapping_flag indicates whether a linear dynamic rangetransformation method is used. When the linear dynamic rangetransformation method is used, linear_mapping flag has a value of 1.

luma_clipping_upper_bound indicates a digital value of an upper criticalpoint in a dynamic range (DR) displayed when the clipping option isused.

luma_clipping_lower_bound indicates a digital value of a lower criticalpoint in the dynamic range (DR) displayed when the clipping option isused.

luminance_upper_bound indicates a maximum value (in nit) of a dynamicrange that needs to be mandatorily represented among dynamic rangesrepresented in UHD broadcast content. luminance_upper_bound may be acriterion for determination of a display type of a receiving device.Further, luminance_upper_bound may signal an additional criterion fordetermination of a display type of a receiving device.

luminance_lower_bound indicates a minimum value (in nit) of a dynamicrange that needs to be mandatorily represented among dynamic rangesrepresented in UHD broadcast content. luminance_lower_bound may be acriterion for determination of a display type of a receiving device.Further, luminance_lower_bound may signal an additional criterion fordetermination of a display type of a receiving device.

luma_upper_value indicates a digital value corresponding toluminance_upper_bound.

luma_lower_value indicates a digital value corresponding toluminance_lower_bound.

mid_DR_transformation_curve_type identifies a DR transformation curveused in a mid dynamic range. One of a linear curve, an exponentialcurve, an S-curve, a logarithmic curve, a combination curve and alook-up table (LTU) may be used as a transformation curve.

mid_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified bymid_DR_transformation_curve_type. For example, gradient information canbe transmitted when a linear curve is used, information on a base can betransmitted when an exponential curve or a logarithmic curve is used,information about coordinates of an inflection point and a base and ay-intercept of each section can be transmitted when an S-curve is used,and information about an x-coordinate of each section, a curve type ofeach section and the corresponding graph can be transmitted when acombination curve is used.

mid_DR_percentage indicates the percentage of a mid dynamic range amongdynamic ranges of UHD broadcast content, which occupies the entiredynamic range of a receiver display.

upper_DR_transformation_curve_type identifies a dynamic rangetransformation curve used in an upper dynamic range. One of a linearcurve, an exponential curve, an S-curve, a logarithmic curve, acombination curve and a look-up table (LTU) may be used as atransformation curve.

upper_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified byupper_DR_transformation_curve_type. For example, gradient informationcan be transmitted when a linear curve is used, information on a basecan be transmitted when an exponential curve or a logarithmic curve isused, information about coordinates of an inflection point and a baseand a y-intercept of each section can be transmitted when an S-curve isused, and information about an x-coordinate of each section, a curvetype of each section and the corresponding graph can be transmitted whena combination curve is used.

upper_DR_percentage indicates the percentage of an upper dynamic rangeamong dynamic ranges of UHD broadcast content, which occupies the entiredynamic range of a receiver display.

lower_DR_transformation_curve_type identifies a dynamic rangetransformation curve used in a lower dynamic range. One of a linearcurve, an exponential curve, an S-curve, a logarithmic curve, acombination curve and a look-up table (LTU) may be used as atransformation curve.

lower_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified bylower_DR_transformation_curve_type. For example, gradient informationcan be transmitted when a linear curve is used, information on a basecan be transmitted when an exponential curve or a logarithmic curve isused, information about coordinates of an inflection point and a baseand a y-intercept of each section can be transmitted when an S-curve isused, and information about an x-coordinate of each section, a curvetype of each section and the corresponding graph can be transmitted whena combination curve is used.

number_luminance_upper_bound_diff indicates the number of variables usedto extend a mid dynamic range.

luminance_upper_bound_diff[i] indicates a difference value forconstituting an (i+1)-th luminance value in UHD broadcast content. Whena mid dynamic range is extended in a display which has a wider dynamicrange than an existing dynamic range but cannot accommodate all dynamicranges represented in UHD broadcast content (case 2),luminance_upper_bound can be changed to a value indicated byluminance_upper_bound+luminance_upper_bound_diff[0]+ . . .+luminance_upper_bound_diff[i].

luma_upper_value_diff[i] indicates a digital value corresponding to an(i+1)-th luminance value in UHD broadcast content. When a mid dynamicrange is extended in a display which has a wider dynamic range than anexisting dynamic range but cannot accommodate all dynamic rangesrepresented in UHD broadcast content (case 2), luma_upper_value can bechanged to a value indicated byluma_upper_value+luma_upper_value_diff[0]+ . . .+luma_upper_value_diff[i].

upper_DR_transformation_curve_type[i] can identify a transformationcurve used in a changed upper dynamic range when an (i+1)-th dynamicrange is supported. That is, when a mid dynamic range is extended,upper_DR_transformation_curve_type[i] can identify a transformationcurve used in an upper dynamic range changed according to the extendedmid dynamic range.

upper_DR_transformation_curve( ) indicates additional informationaccording to a transformation curve identified byupper_DR_transformation_curve_type[i]. That is,upper_DR_transformation_curve( ) indicates details of a transformationcurve used in a changed upper dynamic range when an (i+1)-th dynamicrange is supported.

upper_DR_percentage[i] indicates the percentage of a changed upperdynamic range, which occupies the entire dynamic range of a receiverdisplay, when a mid dynamic range of UHD broadcast content is changed.

mid_DR_percentage[i] indicates the percentage of a changed mid dynamicrange which occupies the entire dynamic range of a receiver display whena mid dynamic range of UHD broadcast content is changed.

FIG. 10 illustrates a case in which an SEI message defined in HEVCaccording to an embodiment of the present invention is referred to. Whencolor_gamut_mapping_info_type described in the lower part of FIG. 7 isset to 0x00, gamut_mapping_info( ) is not directly defined inHDR_video_info descriptor and the SEI message defined in HEVC can bereferred to. Here, the SEI message can comply with a color remappinginformation SEI message syntax defined in HEVC.

When HDR_video_info_type is common type as common HDR metadata relatedto mastering display or video, referenced information can be used forthe entire video. When HDR_video_info_type is scene type or frame typeas scene/frame HDR metadata, referenced information can be applied onlyto a corresponding section.

FIGS. 11 and 12 illustrate an embodiment of signaling HDR_video_infodescriptor according to an embodiment of the present invention through aPMT. The PMT refers to a program mapping table and may include table IDinformation, section syntax indicator information, section lengthinformation, program number information, version number information,current_next indicator information, section number information, PCR_PIDinformation, program info length information, first descriptorinformation, stream type information, elementary PID information,elementary stream length (Es_info_length) information, second descriptorinformation, CRC information, etc. The first descriptor information canrefer to descriptor information included in the first loop following theprogram info length information and the second descriptor informationcan refer to descriptor information included in the second loopfollowing the Es_info_length information.

UHD_program_info_descriptor according to an embodiment of the presentinvention can be signaled by being included in the first descriptorinformation included in the PMT, and the aforementioned HDR_video_infodescriptor can be signaled by being included in the second descriptorinformation included in the PMT.

UHD_program_info_descriptor may include at least one of descriptor_tag,descriptor_length and UHD_service_type as shown in the upper part ofFIG. 12. Here, UHD_service_type can refer to the type of a UHD serviceas shown in the lower part of FIG. 12. For example, UHD_service_type canindicate a UHD service type designated by a user, such as UHD1(4K),UHD2(8K) or a type classified by quality. Various UHD services can beprovided to a receiver through UHD_service_type. The present inventioncan indicate provision of HDR video info regarding different stages orunits such as video, scenes or frames by setting UHD_service_type=1100(UHD1 service with HDR video information metadata; an example of 4K).

FIGS. 13 and 14 illustrate an embodiment of signaling HDR_video_infodescriptor according to an embodiment of the present invention throughan EIT. ATSC and DVB systems may include the EIT as a signaling table.Syntaxes included in the EIT are shown in FIGS. 12 and 13.

The EIT (Event Information Table) of ATSC and DVB systems according toan embodiment of the present invention may commonly include a table_idfield, a section_syntax_indicator field, a section_length field, asource_id (service_id) field, a version_number field, acurrent_next_indicator field, a section_number field, alast_section_number field, a num_events_in_section(segment_last_section_number) field, an event_id field, a start_timefield, a length_in_seconds (duration) field, a descriptors_length field,a descriptor( ) field and/or a CRC_32 field.

The table_id field indicates that the corresponding table is an EIT(Event Information Table). The section_syntax_indicator field is a 1-bitfield which is set to 1 to indicate a long format of an MPEG-2private_section table. The section_length field indicates the length ofa table section following this field in bytes. The source_id fieldindicates a source ID of a virtual channel carrying an event describedin the corresponding section. The version_number field is a 5-bit fieldindicating a version number of the table. The current_next_indicatorfield is a 1-bit field which indicates whether the table is currentlyapplicable or applicable later. The section_number field indicates asection number. The last_section_number field identifies the number ofthe last section. The num_events_in_section field indicates the numberof events included in the corresponding table section. The event_idfield identifies a specific number indicating a described event. Thestart_time field indicates a start time of the corresponding event onthe basis of GPS time in seconds. A value indicating a start time of anevent may be greater than a value indicating an expiration time of anevent which is being broadcast on a virtual channel. The expiration timeof an event can be defined as the sum of the start time of the event andthe duration of the event. The length_in_seconds (duration) fieldindicates a duration of an event in seconds. The descriptors_lengthfield indicates the length of descriptor( ) described following thisfield. The descriptor( ) is a descriptor loop located within the table.The descriptor loop may include an additional descriptor. The EIT mayinclude zero or more descriptors, and the relevant descriptor maycorrespond to an event level descriptor which describes informationapplied to each event. According to an embodiment of the presentinvention, UHD_program_info_descriptor and HDR_video_info descriptor canbe included in the event level descriptor and delivered.UHD_program_info_descriptor may be used to identify a UHD service type.Whether HDR_video_info descriptor includes HDR video informationmetadata may be checked at the event level, and HDR_video_infodescriptor may be used to determine whether a receiver can accommodatethe HDR video information metadata. In the case of cable broadcast, thesame information may be provided to an AEIT instead of theaforementioned descriptors.

The CRC_32 field includes a CRC value used to check data integrity. TheCRC value can guarantee output of “0” from a register included in adecoder defined in Annex A of ISO-13818-1 “MPEG-2 Systems” after all EITsections are processed.

When UHD_service_type of UHD_program_info_descriptor signaled throughthe EIT is set to 1100, the receiver can confirm that information aboutan appropriate viewing condition is delivered through metadata. Forexample, when UHD_service_type is 1100, the receiver can confirm thatthe corresponding service is UHD1 service with HDR video informationmetadata, 4K.

When UHD_service_type of UHD_program_info_descriptor signaled throughthe EIT is set to 0000, the receiver can check whetherHDR_video_info_descriptor( ) is present and recognize provision of HDRvideo info regarding different stages or units such as video, scenes orframes. Here, UHD_service_type of 0000 can indicate UHD1 service.

In the above case, it is possible to determine whether information inunits of mastering display, content, scene or frame, which a contentprovider desires, can be used in a viewer's display usingHDR_video_info_descriptor( ). By using HDR_video_ it is possible topreviously determine whether content, scene or frame based metadata isused for content currently played or played later and a receiver canprepare setting for a situation such as scheduled recording.

FIG. 15 illustrates HDR_video_info_descriptor( ) according to anotherembodiment of the present invention. A plurality of pieces ofinformation may be present for one event. That is, information is notconsistently applied to content but applied information can be changedaccording to time or presence or absence of inserted content.Alternatively, various modes intended by a producer may be supported forone piece of content. Here, it is necessary to determine whether areceiver display can accommodate such modes, and information thereaboutcan be provided by a broadcast transmission device throughviewing_condition_metadata. A syntax in viewing_condition_metadata cancomply with the definition of the viewing condition descriptor of theSEI message.

HDR_video_info_descriptor may include at least one of descriptor_tag,descriptor_length and number_of_info as shown in the upper part of FIG.15. HDR_video_info_descriptor may include a loop and can include as manypieces of HDR_video_info_metadata( ) as the number indicated bynumber_of_info. The syntax of HDR_video_info_metadata( ) is as shown inthe lower part of FIG. 15 and may include the following information.

HDR_video_info_type can indicate a unit of application of information inthe HDR video information descriptor. That is, application units can bedivided into common application to a video clip (common type),application in consecutive scenes (scene type) and application to eachframe (frame type). The aforementioned common HDR metadata may berepresented as the common type and the scene/frame HDR metadata may berepresented as the scene type or frame type. A broadcast transmissiondevice can set HDR_video_info_type to the common type and transmitinformation about content in order to deliver common type information.Further, the broadcast transmission device may transmit informationwhich refers to an SEI message in order to deliver the common typeinformation. In this case, a receiver can use a predetermined SEImessage as the common type information. For example, the broadcasttransmission device can designate an SEI message included in HEVC or amastering display color volume SEI message as an SEI message which is areference target. In addition, the broadcast transmission device maytransmit information about mastering display in order to deliver thecommon type information. In this case, the receiver can receive theinformation about mastering display and use the information as commontype information. Furthermore, a knee function information SEI messageor a color remapping information SEI message among HEVC SEI messages maybe delivered to be uniformly applied to entire content. If suchinformation changes with time, for example, according to scenes orframes, it is possible to set HDR_video_info_type to the scene type orframe type and deliver the corresponding SEI message or detailedinformation, thereby indicating that the information is applied only tosome scenes or frames of content with time.

dynamic_range_mapping_info_present_flag can indicate that the descriptorincludes dynamic range mapping related information.

color_gamut_mapping_info_present_flag can indicate that the descriptorincludes gamut mapping related information.

viewing_condition_info_present_flag can indicate that the descriptorincludes viewing condition related information.

HDR_video_enhancement_info_present_type can indicate whether informationregarding each scene or frame is additionally delivered. For example,HDR_video_info_type corresponds to the common type,HDR_video_enhancement_info_present_type can indicate whether dynamicrange mapping and gamut mapping related information is additionallydelivered. Here, a function of additional information can be defined perframe or scene. A function of additional information may be dynamicrange mapping or gamut mapping. Accordingly, the receiver can prepareprocessing operation for additional information.

Sync_info_type can indicate a method of representing information forsynchronization with video, a scene or a frame to which information inthe HDR video information descriptor needs to be applied. For example,sync_info_type can deliver a picture order count (POC) value used in adecoder or directly deliver a pic_order_count_lsb value. In the case ofstorage media, media time information can be used, and the number ofaccumulated frames on the basis of a reference time for video start maybe decided as sync_info_type.

Sync_start is information related to synchronization start time. Wheninformation is delivered in a specific period such as an RAP instead ofbeing delivered per frame, it is necessary to connect the start and endof a period in which the information is used to video frames. Thepresent invention may apply an embodiment of representing startinformation of the period or a frame to which the correspondinginformation is applied as information such as a time, a POC, the numberof frames or PTS in association with sync_info_type using sync_start.Sync_info_type can define a synchronization information type as a time,a time difference, start order, a POC (picture order count), PTS or thenumber of aggregated frames.

Sync_duration is information about a duration starting from sync_start.A synchronization expiration timing can be calculated assync_start+sync_duration as in the aforementioned example, andsynchronization expiration timing information may be directly deliveredalong with or instead of sync_duration as necessary. In the case of livebroadcast, an expiration time cannot be determined in advance and thusmay be set to a predetermined value such as FFFF. If the metadataapplication timing can be determined only with the sync_startinformation, sync_duration may not be used. In this case, sync_durationmay be used as a flag that provides additional information such asinformation indicating whether other metadata is transmitted followingthe corresponding metadata.

Number_of_dynamic_range_info can indicate the number of methods ofrepresenting dynamic range information corresponding to masteringdisplay, video, a scene or a frame.

Dynamic_range_info_type indicates a method of representing dynamic rangeinformation corresponding to mastering display, video, a scene or aframe. Methods for representing a dynamic range may be as shown in thelower part of FIG. 6. A dynamic range can be represented using at leastone of maximum luminance, minimum luminance, average luminance, and anaverage or median value composed of a specific component. Further, whitemay be subdivided into normal white, diffuse white and specular whiteaccording to characteristics and black may be classified into normalblack, deep black and pitch dark according to characteristics andpresented.

Transfer_function_type can indicate the type of a transfer function usedfor mastering display, video, a scene or a frame of HDR video. Forexample, predetermined EOTF such as SMPTE ST 2084, ITU BT.1886 andBT.2020 can be signaled. Luminance representation methods may be dividedinto an absolute luminance representation method and a relativeluminance representation method depending on the type of a transferfunction and a specific method may be signaled. A coefficient of anarbitrary transfer function may be delivered as necessary.

Color_gamut_type can indicate a color gamut type corresponding tomastering display, video, a scene or a frame of HDR video. For example,color_gamut_type can indicate a standard color gamut such as BT.709,BT.2020 and DCI-P3 or indicate an arbitrary color gamut through RGBcolor primary (XYZ, RGBW and the like may be used) as necessary.

Color_temperature_type can indicate information about standard whitecorresponding to mastering display, video, a scene or a frame of a colorgamut. For example, color_temperature_type may be a standard lightsource color temperature such as D65 and D50 and may indicate anarbitrary value representative of a color temperature such as RGB colorprimary (XYZ, RGBW and the like are possible) with respect to white asnecessary.

Dynamic_range_mapping_info_type indicates the type of dynamic rangemapping information corresponding to mastering display, video, a sceneor a frame. For example, dynamic_range_mapping_info_type can refer to aknee function information SEI message or a tone mapping information SEImessage included in HEVC, as shown in the upper part of FIG. 7.Furthermore, dynamic_range_mapping_info_type may be directly describedin a predetermined HDR video information descriptor.

Color_gamut_mapping_info_type indicates the type of color gamut mappinginformation corresponding to mastering display, video, a scene or aframe. For example, color_gamut_mapping_info_type can refer toinformation defined in a color remapping information SEI messageincluded in HEVC, as shown in the low part of FIG. 7. Further,color_gamut_mapping_info_type may be directly described in apredetermined HDR video information descriptor.

Viewing_condition_info_type indicates the type of viewing conditioninformation corresponding to video, a scene or a frame. For example,viewing_condition_info_type may refer to information defined inviewing_condition defined as a separate SEI message and may be directlydescribed in a predetermined HDR video information descriptor.

FIG. 16 is a block diagram of a receiver, which illustrates an operationmethod according to an embodiment of the present invention. When HDRvideo information is transmitted through the aforementioned method, thereceiver analyzes a signal and applies information to HDR video on thebasis of the analyzed signal through the following process.

The receiver according to an embodiment of the present invention mayreceive a broadcast signal from a radio frequency (RF) channel using atuner and a demodulator 1601. The broadcast signal may be receivedthrough other paths (not shown) as well as an RF channel. For example,the broadcast signal can be received through IP basedbroadcast/communication, wired/wireless communication and wired/wirelessinterfaces. Further, the broadcast signal and metadata which will bedescribed below may be received through different paths. The metadatawhich will be described below may be transmitted and received throughother paths (e.g., IP based broadcast/communication, wired/wirelesscommunication, wired/wireless interfaces, short-range wirelesscommunication, etc.) as well as broadcast signals.

The receiver may decode the received broadcast signal using a channeldecoder 1602. Here, the channel decoder may decode the broadcast signalusing VSB or QAM. The decoded broadcast signal may be demultiplexed intobroadcast content data and signaling data by a demultiplexer 1603. Thebroadcast content data may include HDR video data and may be decoded bya video decoder 1605. The signaling data may include information aboutthe broadcast content data and include a signaling table or signalinginformation such as a PMT, a VCT, an EIT or an SDT according to anembodiment. The receiver may extract UHD_program_info_descriptor fromthe signaling information (e.g., a PMT) using a section data processor1604.

The receiver checks whether there are additional services or media thatthe receiver needs to additionally receive in order to constituteoriginal UHDTV broadcast using UHD_program_info_descriptor. In anembodiment of the present invention, the receiver can recognize presenceof additional information through an SEI message upon reception ofUHD_service_type=1100. Alternatively, the receiver can recognizepresence of video related additional information through an SEI messageusing an EIT upon receiving UHD_service_type=0000 (8K is 0001).

Upon recognition of presence of additional information, the receiver mayacquire information about HDR video through an HDR video information SEImessage or HDR_video_info_descriptor ( ) of an EIT.

According to an embodiment of the present invention, the receiver maydetermine whether the additional information is applied to the entirecontent or a scene or a frame on the basis of HDR_video_info_typeincluded in HDR_video_info_descriptor( ) Further, to synchronizeadditional information application ranges in each case,HDR_video_info_descriptor( ) may include information about start timeand expiration time of the additional information. In an embodiment ofthe present invention, sync_info_type, sync_start andsync_durationvideo, which are information for synchronization on thebasis of frames, are used.

When HDR_video_info_type is information applied to entire content,signaling information can signal whether information in units of sceneor frame is additionally provided throughHDR_video_enhancement_info_present_type. Accordingly, the receiver canrecognize that information in units of scene or frame is provided inadvance and prepare setting for metadata processing in units of scene orframe and HDR video quality enhancement.

The receiver may recognize the type of information regarding highcontrast or information representing luminance as information capable orrepresenting a dynamic range through signaling information usingdynamic_range_info_type. For example, dynamic_range_info_type canindicate an aspect ratio and f-stop as high contrast information andindicate peak luminance and minimum luminance as luminance information.A value according to each type may be delivered to the receiver throughdynamic_range_info_value[i]. Particularly, according to an embodiment ofthe present invention, dynamic ranges according to characteristics ofcontent, mastering display, a frame and a scene can be represented, andluminance can be subdivided and represented throughdynamic_range_info_type. In addition, the receiver can recognize an EOTFtype, a color gamut type and a color temperature type used for colorencoding through transfer_function_type, color_gamut_type andcolor_temperature_type.

HDR_video_info_descriptor( ) is additional information which providesdynamic range mapping, color gamut mapping and viewing conditioninformation to the receiver. When there are various additionalinformation provision methods, an SEI message defined in HEVC or apredetermined SEI message may be designated for each method throughdynamic_range_mapping_info_type, color_gamut_mapping_info_type andviewing_condition_info_type. When additional information is directlydefined in HDR_video_info descriptor, the receiver can recognizedetailed information through dynamic_range_mapping_info( ),color_gamut_mapping_info( ) and viewing_condition_info( ).

The aforementioned signaling information may be stored in a metadataprocessor 1606 of the receiver. The stored signaling information may beupdated when the aforementioned set number or version is changed. Thereceiver may synchronize video quality enhancement information(signaling information) stored in the metadata processor 1606 with videodata using a synchronizer 1607 such that the video quality enhancementinformation can be applied to the video data according to an applicationunit.

The receiver may deliver dynamic range information in units of content,scene or frame to an HDR algorithm or a video quality enhancement unitsuch as an existing post processor 1608 (post-processing module) on thebasis of information provided thereto, to achieve video qualityenhancement. In addition, when there is detailed information related todynamic range mapping, color gamut mapping and viewing conditioninformation, the receiver may directly connect related modules such astone mapping, color mapping, color correction and white balance modulesto achieve video quality enhancement. If video processing is performedin a linear luminance domain in the receiver, EOTF recognized throughtransfer_function_type can be applied.

The receiver may display post-processed HDR video through a display unit1609 to provide the HDR video to a user.

FIG. 17 is a block diagram of a broadcast transmitter according to anembodiment of the present invention. A broadcast transmitter 1701according to the present invention may include an encoder 1702, amultiplexer 1703 and/or a transmission unit 1704.

The resolution of video data input to the broadcast transmitter 1704 maybe UHD. Metadata input to the broadcast transmitter 1701 may includevideo quality enhancement metadata with respect to UHD video. Asdescribed above with reference to FIGS. 4 to 7, the video qualityenhancement metadata may include HDR_video_info_descriptor ( ) andinformation necessary for UHD video quality enhancement. The informationnecessary for UHD video quality enhancement may be applied to entirecontent or applied on a scene-by-scene or frame-by-frame basis and mayinclude common HDR metadata applied to the entire content andscene/frame HDR metadata applied on a scene-by-scene or frame-by-framebasis.

The video data input to the broadcast transmitter 1701 may be encoded bythe encoder 1702. A transmission end may use HEVC (High Efficiency VideoCoding) as a video data encoding scheme. The transmission end maysynchronize the encoded video data with the video quality enhancementmetadata and multiplex the synchronized data using the multiplexer 1703.The video quality enhancement metadata may further includesynchronization information. The video quality enhancement metadata mayinclude synchronization information such as time, a time difference,start order, a POC, a PTS and the number of accumulated frames accordingto synchronization methods.

The transmission unit 1704 may transmit a transport stream output fromthe multiplexer 1703 as a broadcast signal. Here, the transport streammay be channel-coded and modulated and then transmitted as a broadcastsignal. According to another embodiment of the present invention, themetadata may be transmitted through other paths (e.g., IP basedbroadcast/communication, wired/wireless communication, wired/wirelessinterfaces and short-range wireless communication) as well as thebroadcast signal. Further, the metadata may be transmitted through adifferent path from a path through which video data is transmitted.

FIG. 18 is a block diagram of a broadcast receiver according to anembodiment of the present invention. A broadcast receiver 1801 accordingto the present invention may include a reception unit 1802, ademultiplexer 1803 and/or a decoder 1804.

A broadcast signal received by the reception unit 1802 may bedemodulated and then channel-decoded. The channel-decoded broadcastsignal may be input to the demultiplexer 1803 to be demultiplexed into avideo stream and video quality enhancement metadata. The metadata may bereceived through other paths (e.g., IP based broadcast/communication,wired/wireless communication, wired/wireless interfaces and short-rangewireless communication) as well as the broadcast signal. The output ofthe demultiplexer may be input to the decoder 1804. The decoder mayinclude a video decoder and a metadata processor. That is, the videostream can be decoded by the video decoder and the video qualityenhancement metadata can be decoded by the metadata processor. Thedecoded video stream and video quality enhancement metadata may be usedfor UHD video quality enhancement by the post processor, as describedwith reference to FIG. 16. The receiver can post-process the decodedvideo signal on the basis of the video quality enhancement metadata andenhance video quality of the video data for at least one of HDR and WCG.

FIG. 19 illustrates a method of transmitting a broadcast signalincluding video quality enhancement metadata according to an embodimentof the present invention. The method of transmitting a broadcast signalincluding video quality enhancement metadata may include a step S1910 ofencoding a video stream to generate video data, a step S1920 ofgenerating a broadcast signal including the generated video data andvideo quality enhancement metadata, and a step S1930 of transmitting thegenerated broadcast signal.

In step S1910 of encoding a video stream to generate video data, a UHDvideo stream may be received and encoded to generate video data. Here,the video stream may be encoded using HEVC (High Efficiency VideoCoding). In step S1910 of generating video data, the video qualityenhancement metadata may be generated. As described above, the broadcasttransmission device can generate the video quality enhancement metadatawhich is applied to entire content, a scene or a frame of the video datain step S1910 of generating the video data. The video qualityenhancement metadata may be data with respect to at least one of HDR andWCG and may have different quantities of information depending onapplication units. Further, the video quality enhancement metadata maybe directly defined in signaling information or generated by referringto another message. Such video quality enhancement metadata may bereference data used for the receiver to enhance video quality of videodata according to application unit. Consequently, the receiver candynamically enhance video quality of video data using the video qualityenhancement metadata received along with the video data.

In step S1920 of generating a broadcast signal including the generatedvideo data and video quality enhancement metadata, a broadcast signalframe may be built and modulated to generate a broadcast signal.

In step S1930 of transmitting the generated broadcast signal, atransport stream may be transmitted as the broadcast signal.

FIG. 20 illustrates a method of receiving a broadcast signal includingvideo quality enhancement metadata according to an embodiment of thepresent invention. The method of receiving a broadcast signal includingvideo quality enhancement metadata may include a step S2010 of receivinga broadcast signal, a step S2020 of demultiplexing the receivedbroadcast signal into video data and video quality enhancement metadataand a step S2030 of decoding and applying the video data and the videoquality enhancement metadata.

In step S2010 of receiving a broadcast signal, the broadcast signal maybe received using a reception unit, demodulated and thenchannel-decoded. The broadcast signal may include a UHD broadcast signaland may further include video quality enhancement metadata with respectto UHD broadcast content. The video quality enhancement metadata hasbeen described in detail with reference to FIGS. 4 to 15.

In step S2020 of demultiplexing the received broadcast signal into thevideo data and the video quality enhancement metadata, thechannel-decoded broadcast signal may be demultiplexed into the videodata and the video quality enhancement metadata using a demultiplexer.The video data may include UHD video data and the video qualityenhancement metadata may include HDR or WCG related data applied to theUHD video data. Here, the video quality enhancement metadata may bedivided into common HDR metadata and scene/frame HDR metadata accordingto application range thereof. The video quality enhancement metadata mayinclude at least one of the common HDR metadata and the scene/frame HDRmetadata. The common HDR metadata may be information applied to allvideo data constituting one piece of content and the scene/frame HDRmetadata may be data applied to some scenes or frames of the video data.The video quality enhancement metadata may be directly defined insignaling information of the broadcast signal or a previously definedmessage may be referred to.

In step S2030 of decoding and applying the video data and the videoquality enhancement metadata, the video data may be decoded using avideo decoder to acquire the video data. In this step, the video qualityenhancement metadata can be acquired using a signaling data parser or ametadata decoder. The receiver can enhance video quality of the decodedvideo data on the basis of the video quality enhancement metadata. Thevideo quality enhancement metadata may include HDR or WCG informationregarding the video data and may further include synchronizationinformation indicating an information application time. The videoquality enhancement metadata may be applied to the video data on thebasis of the synchronization information. Accordingly, video qualityenhancement can be applied to all video data or applied per section. Auser can be provided with UHD content with enhanced video qualitythrough HDR or WCG information additionally applied to previous UHDcontent.

Although the description of the present invention is explained withreference to each of the accompanying drawings for clarity, it ispossible to design new embodiment(s) by merging the embodiments shown inthe accompanying drawings with each other. Additionally, if a recordingmedium readable by a computer, in which programs for executing theembodiments mentioned in the foregoing description are recorded, isdesigned by those skilled in the art, this is within the scope of theappended claims and their equivalents.

An apparatus and method according to the present invention may benon-limited by the configurations and methods of the embodimentsmentioned in the foregoing description. In addition, the embodimentsmentioned in the foregoing description may be configured in a manner ofbeing selectively combined with one another entirely or in part toenable various modifications.

In addition, a method according to the present invention may beimplemented with processor-readable code in a processor-readablerecording medium provided to a network device. The processor-readablemedium may include all kinds of recording devices capable of storingdata readable by a processor. The processor-readable medium may includeone of ROM, RAM, CD-ROM, magnetic tapes, floppy disks, optical datastorage devices, and the like for example and also include acarrier-wave type implementation such as a transmission via Internet.Furthermore, as the processor-readable recording medium is distributedto a computer system connected via network, processor-readable code maybe saved and executed according to a distributed system.

It will be appreciated by those skilled in the art that variousmodifications and variations may be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both the product invention and the process invention are described inthe specification and the description of both inventions may besupplementarily applied as needed.

MODE FOR INVENTION

Various embodiments have been described in the best mode for carryingout the invention.

INDUSTRIAL APPLICABILITY

The present invention can be used for broadcast and video signalprocessing and is reproducible and industrially applicable.

1-14. (canceled)
 15. A method of transmitting a broadcast signal,comprising: encoding, by an encoder, High Efficiency Video Coding (HEVC)video data including a Supplemental Enhancement Information (SEI)message for video quality enhancement; generating, by a multiplexer, abroadcast signal including the encoded HEVC video data; andtransmitting, by a transmitter, the generated broadcast signal, whereinthe SEI message for video quality enhancement includes luminanceinformation being applicable to the encoded HEVC video data.
 16. Themethod according to claim 15, wherein the SEI message for the videoquality enhancement further includes flag information indicating whetherluminance information is included in the SEI message or not.
 17. Themethod according to claim 16, wherein the SEI message for the videoquality enhancement further includes information for applying theluminance information to the encoded HEVC video data based on a pictureorder count of the encoded HEVC video data.
 18. The method according toclaim 17, wherein the luminance information includes maximum luminanceinformation, minimum luminance information and average luminanceinformation for the encoded HEVC video data.
 19. The method according toclaim 15, wherein the SEI message for the video quality enhancementfurther includes synchronization information indicating a time at whichthe luminance information is applied to the encoded HEVC video data. 20.The method according to claim 15, wherein the SEI message for the videoquality enhancement further includes type information indicating anapplication range of the luminance information.
 21. A method ofreceiving a broadcast signal, comprising: receiving a broadcast signalincluding High Efficiency Video Coding (HEVC) video data with asupplemental enhancement information (SEI) message for video qualityenhancement; demultiplexing the broadcast signal into the HEVC videodata and the SEI message for the video quality enhancement; decoding theHEVC video data and the SEI message for the video quality enhancement;and applying luminance information included in the SEI message for thevideo quality enhancement to the decoded HEVC video data.
 22. The methodaccording to claim 21, wherein the SEI message for the video qualityenhancement includes flag information indicating whether luminanceinformation is included in the SEI message or not.
 23. The methodaccording to claim 22, wherein the SEI message for the video qualityenhancement further includes information for applying the luminanceinformation to the decoded HEVC video data based on a picture ordercount of the decoded HEVC video data.
 24. The method according to claim23, wherein the luminance information includes maximum luminanceinformation, minimum luminance information and average luminanceinformation for the decoded HEVC video data.
 25. The method according toclaim 21, wherein the SEI message for the video quality enhancementfurther includes synchronization information indicating a time at whichthe luminance information is applied to the decoded HEVC video data. 26.The method according to claim 21, wherein the SEI message for the videoquality enhancement further includes type information indicating anapplication range of the luminance information.
 27. A broadcast signaltransmission device comprising: an encoder to encode High EfficiencyVideo Coding (HEVC) video data including a Supplemental EnhancementInformation (SEI) message for video quality enhancement; a multiplexerto generate a broadcast signal including the encoded HEVC video data;and a transmitter to transmit the generated broadcast signal, whereinthe SEI message for video quality enhancement includes luminanceinformation being applicable to the encoded HEVC video data.
 28. Abroadcast signal reception device comprising: a receiver to receive abroadcast signal including High Efficiency Video Coding (HEVC) videodata with a supplemental enhancement information (SEI) message for videoquality enhancement; a demultiplexer to demultiplex the broadcast signalinto the HEVC video data and the SEI message for the video qualityenhancement; a decoder to decode the HEVC video data and the SEI messagefor the video quality enhancement; and a post processor to applyluminance information included in the SEI message for the video qualityenhancement to the decoded HEVC video data.